So there is a notebook that has Scientific Linux 6.3 installed with GNOME 2.

If we don't press any button on the keyboard or move the mouse, the screen of it turns black.

But: if we move the mouse/hit a button when the screen of it went black.. it still stays black.. it's not a hardware problem, it's a problem related to the OS. I didn't find any energy saving options for this in the BIOS.

If the screen is black, we can slightly see that the OS is still running, but it's very-very-very dark..

The only solution is to press the power-on button for 5 seconds to turn the machine off..

Any solutions/settings? Please halp.

UPDATE#1: (I can only rarely get to this notebook, that's why I can only answer rarely, sorry) So I found a settings in gnome-screensaver-preferences: "Activate screensaver when computer is idle" was enabled. I disabled it, and we are waiting for the blank screen to appear again, but this takes time, because I found out that the screen goes to blank randomly (!). Even if there was somebody in front of the notebook and was using the ex.: USB mouse.. strange.. I will update the Q/accept the good answer if this helps:D

Try running $xset -q or xset -q | grep timeout and xset -q | grep Standby and see if the output is something like this respectively:

timeout: 0 cycle: 600
Standby: 0 Suspend: 0 Off: 0

Gnome should let you set the values for Standby, Suspend and Off to 0 through their power saving settings related to the display. The first part, timeout, is related to the screensaver, but you should be able to set it to 0 with this command: